Miller Ethan J, Trewby William, Farokh Payam Amir, Piantanida Luca, Cafolla Clodomiro, Voïtchovsky Kislon
Physics Department, Durham University.
Physics Department, Durham University;
J Vis Exp. 2016 Dec 20(118):54924. doi: 10.3791/54924.
Atomic force microscopy (AFM) has become a well-established technique for nanoscale imaging of samples in air and in liquid. Recent studies have shown that when operated in amplitude-modulation (tapping) mode, atomic or molecular-level resolution images can be achieved over a wide range of soft and hard samples in liquid. In these situations, small oscillation amplitudes (SAM-AFM) enhance the resolution by exploiting the solvated liquid at the surface of the sample. Although the technique has been successfully applied across fields as diverse as materials science, biology and biophysics and surface chemistry, obtaining high-resolution images in liquid can still remain challenging for novice users. This is partly due to the large number of variables to control and optimize such as the choice of cantilever, the sample preparation, and the correct manipulation of the imaging parameters. Here, we present a protocol for achieving high-resolution images of hard and soft samples in fluid using SAM-AFM on a commercial instrument. Our goal is to provide a step-by-step practical guide to achieving high-resolution images, including the cleaning and preparation of the apparatus and the sample, the choice of cantilever and optimization of the imaging parameters. For each step, we explain the scientific rationale behind our choices to facilitate the adaptation of the methodology to every user's specific system.
原子力显微镜（AFM）已成为一种成熟的技术，用于在空气和液体中对样品进行纳米级成像。最近的研究表明，当以振幅调制（轻敲）模式操作时，在液体中对各种软硬样品都能获得原子或分子水平分辨率的图像。在这些情况下，小振荡幅度（SAM-AFM）通过利用样品表面的溶剂化液体来提高分辨率。尽管该技术已成功应用于材料科学、生物学、生物物理学和表面化学等多个领域，但对于新手用户来说，在液体中获得高分辨率图像仍然具有挑战性。部分原因是需要控制和优化大量变量，如悬臂的选择、样品制备以及成像参数的正确操作。在此，我们展示了一种在商用仪器上使用SAM-AFM在流体中获取软硬样品高分辨率图像的方案。我们的目标是提供一份实现高分辨率图像的分步实用指南，包括仪器和样品的清洁与制备、悬臂的选择以及成像参数的优化。对于每一步，我们都解释了我们选择背后的科学原理，以便于将该方法应用于每个用户的特定系统。
